Perhaps you should try some spelling variations:
"improving contract performance contract." » "improving country performance contract.", "improving court performance contract.", "improving corporate performance contract.", "improving contract performance contracts.", "improve contract performance contract.", "improving central performance contract.", "improving coverage performance contract."
"improving firm performance series." » "improving firm performance metrics.", "improving firm performance reviews.", "improving firm performance review.", "improving _ performance series.", "improving firms performance series.", "improving air performance series.", "improving birth performance series."

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving contract performance contract.") or ("improving firm performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving contract performance contract.") OR ("improving firm performance series.")).
• Removing quotes may allow a broader search: (( improving contract performance contract. ) or ( improving firm performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving contract performance contract.") or ("improving firm performance series."))*.